Home & Garden Columns

About the House: The Question of Capping to Keep Pests Away

By Matt Cantor
Friday April 27, 2007

I guess I have to remember to stay off of my horse else be in danger of falling off and damaging my backside. The industry (if you can call it that) that I’m employed in is fairly new and often mistaken for other adjacent trades (e.g. a friend referred to me as an appraiser the other day) including, not surprisingly, the structural pest control industry (often referred to as termite inspectors).  

Now, don’t get me wrong, I like and respect many folks I know in this business. Some do extraordinarily fine work and provide a vital service, but sadly, this does not cover all comers. There are, in my never-humble opinion a couple of major problems in this industry and, while I’ll try to swerve away form a global analysis of this agglomeration of issues, I will pick one and do a little bit of damage. 

Pest officers, like cardiologist live in their own world with their own set of imperatives. The thing that they do for a living seems, from inside that box to be the center of the universe and the rules, activities and theories that apply to their livelihood appear, from their perspective to be the most important things that exist. While some cardiologist might occasionally admit that the oncologist has something of value to say, they will still think it essential for every patient they meet to have a stress test and an EKG. It’s just a feature of being human to have your eyes stuck on your own head and no one else’s.  

For pest control people, the pest report looks like the most important way to look at the house and the repairs recommended in their reports don’t say “fix the rotten wood but be sure to get to the wiring first because a fire is more dangerous than fungal rot,” right? They just say, fix the rot, treat the ground, replace the porch and so on. Part of the problem is also that, if you only meet a cardiologist, you only hear that perspective and if you only see a pest control report, you don’t get a chance to compare those issues to the many other significant ones that might be presented to you by other persons; including home inspectors (he said, polishing his nails on his vest).  

Again, I will find much to agree with on many a pest report but there’s one thing that seems to get included as a recommendation in many of these reports and has for many decades and that is a call for the “capping” of a foundation. 

Capping is analogous to the capping of a tooth. It’s a covering and enlargement that generally extends upward from the original footing and usually has only a very small amount of concrete extending down over the inside edge and rarely much if any on the outside edge. Now why is this done? A cap is done for the simple reason that moisture and insects can more easily get at the bottom wooden elements of the building when the foundation holds these portions up a very short distance off the ground. When this is the case, it doesn’t take much of an accrual of earth along the inside or outside of the footing to allow wood boring inspects to get at the foundation or for wet earth to allow funguses to propagate along the bottom wooden members leading to rot (and there’s nothing dry about it).  

If we can hold the bottom wooden pieces aloft some 6 inches or so from the ground, they tend to fare far better than when these same “mudsills” and other sticks of wood, sit on or near the ground. 

A lot of what we’re talking about relates to termites but they’re not the whole picture when we’re talking about “grade faults,” which is another term for the condition in which wood and earth are getting too intimate. When they’re actually touching each other, we call it earth-to-wood contact, which is, as they say, a bad thing. 

So when pest inspectors see this condition, they often call for a capping of the foundation as a fix for this excess of intimacy (for shame!). The problem is that they are also engaging in the modification of a major structural component of the house without any real consideration for the structural implications. If, the caps were fairly inexpensive and if they were typically built with earthquakes in mind it might not be such a big deal but neither of these things are true. I’ve looked at something in excess of a thousand pest reports (maybe two) in my career and would say that the bids for capping of foundations that I’ve seen are usually somewhere in the range of two-thirds to three-fourths the cost of foundation replacement for the portions of the foundation that were “called.” So this begs an analysis of the difference between a capped foundation and new one (again, we may only be talking about one side or the whole thing). 

Older foundation that get called for capping are generally quite small in overall dimension and have relatively small bearing areas. In other words, the bottom isn’t that broad and they tend to settle more easily as a result. These older foundations often lack metal reinforcement and good quality concrete. Many older footings are imbalanced, bearing too much to the inside and, as a result, tend to tip slowly to the outside (this is called rotation). So when one is capping, one is left with all of these features with only limited improvement. 

Many older caps were installed with little or no interconnection between the old foundation and the cap and rely upon a “cold joint” or friction to hold them together. Today, workmanship is better but the connection is still inferior to the basic demand that foundations be poured integrally so that they will not separate over time. 

I’m darned curious to see what will happened to these caps when an earthquake hits. It may be that the early ones that lack good connection will snap and drop walls with unhappy results. 

New foundations have better balance (usually being an upside-down T shape), well integrated bolting and very hard concrete throughout. So if you can get all of these things for an extra few thousand over an already costly cap, it seems to me a no-brainer. 

I don’t want to blow by that bolting thing too rapidly because, in our earthquake anticipation, it’s a real issue. Caps are often poorly bolted and almost never to the standard required for conventional foundations. Mudsills, those bottom sticks of wood that rest on the foundation often get stuck in the mud, as it were when they get installed in caps. That is to say that they often don’t sit on the concrete but get embedded in the concrete making bracing and some kinds of bolting more difficult. 

A new foundation (or footing section) is required to have at least a moderate number of bolts installed on each section of mudsill so this becomes one more reason to choose a new foundation (or section) over a cap. 

Now, in fairness, some installers will use what is called a “saddle” when beefing up an old foundation. This is cap with one side (or both) that has been dug out and integrated into the cap. This can result in much better bearing and overall strength and I’m certainly much happier when I see one of these (which is rare), but again, I always want to come back to the question of whether a new foundation, with all there is to recommend it, would have cost much more and the answer is usually no. 

`I was asked to comment on such a case the other day and said that I felt that the client would be better off getting a new foundation installed by a cheaper contractor than to take a cap from a better one. While I never really favor working with a lesser individual, the city oversight and the basic requirements on foundations are so stringent that I rarely see a new foundation that’s been done substantially wrong. We can grouse and moan about the code (and city inspectors) all day but this is one proof of their value. You don’t have to worry too much that a foundation will be done wrong, once the drawings and permits are on the table. 

That said, I’d recommend spending a little more and working with the better contractor. It’s an old saw that higher cost is soon forgotten but bad workmanship lives on day after day and I believe it. 

So, do get a pest inspection from time to time and if your pest guy or gal says that you have a “marginal” or “faulty” grade condition and need to cap, ask very nice if they might be willing to give you a comparable bid for new VS the cap. You won’t just be doing well, you’ll be doing good and here’s why. Every person that does this, pushes the marketplace a bit more in the right direction and eventually, we won’t have to sit around and complain about all those lousy contractors. 


Got a question about home repairs and inspections? Send them to Matt Cantor at mgcantor@pacbell.net.